LEVEL LIFT AND DROP-OFF ARRANGEMENT FOR A VACUUM TRANSFER MECHANISM

MONTE-CHARGE A DEPRESSION ET MECANISME DE TRANSPORT

English Abstract

Lightweight moulded pulp trays or the like are attracted upward from transport
on the upper side of
a first conveyor to contact with the underside of the lower run of the
perforated conveyor belt of a
vacuum transfer mechanism by means of vacuum conditions transmitted through
groups of
perforations in said perforated belt, the location of said perforations in
each group, and the timing of
vacuum conditions transmitted through each perforation in each group being
arranged to lift the
forward and rearward proportions of each said product simultaneously with
continuous support
during transport to a selected location for simultaneous release of vacuum
support for said forward
and rearward portions of each said product, whereby to provide a level lift
and drop-off for each
product.

Claims

CLAIMS
1. A level lift and drop-off arrangement for a vacuum lift and transfer
mechanism, said
vacuum lift and transfer mechanism being comprised of a belt conveyor with a
foraminous
belt made of rubber or other plastic material and a vacuum chamber with a
slotted bottom
panel located directly above the lower run of said foraminous belt, said lower
run of said
belt being located directly above and close to the top surfaces of lightweight
products being
transported on a first conveyor, and approaching the terminal end thereof,
said products
being lifted and attracted into contact with the underside of said lower run
of said
foraminous conveyor belt and maintained there by vacuum conditions transmitted
through
the slots of said slotted bottom panel of said vacuum chamber, and thence
through
perforations in said foraminous belt into the space between said foraminous
belt and said
products travelling on said first conveyor, said products then being
transported at the
underside of said foraminous belt to a selected drop-off point beyond the
terminal end of

Page 4
said first conveyor, said vacuum lift and transfer mechanism having a level
lift and drop-off
arrangement where the lower run of said foraminous belt travels in the same
direction as the
lightweight products on said first conveyor and at a controlled speed , and
where said
perforations in said foraminous belt are arranged in groups of at least two
perforations, with
at least one of said groups of said perforations cooperating with each one of
said products
travelling on said first conveyor, with at least one perforation of said group
cooperating
with a rearward portion of said product and at least one other of said
perforations of said
group cooperating with a forward portion of said product, said foraminous belt
being
regulated to travel at precisely the same speed as said products travelling on
said first
conveyor and adjusted to have each product lifted simultaneously by both
rearward and
forward positions of said perforations in said group, the slots in said
slotted bottom panel of
said vacuum chamber being continuous in the direction of travel of said
products with
alternating beginning and drop-off ends coordinating separately with the
forward and
rearward positions of said perforations in said groups, whereby to lift said
forward and
rearward portions of each said product simultaneously and thus maintain a
level position at
the pick-up point, and also to release said forward and rearward portions
simultaneously
whereby to maintain a level position in releasing each said product at a
selected drop-off
point.
2. The level lift and level drop-off arrangement of Claim 1, where the drop-
off point is at a
selected location on a third conveyor, and near the beginning end thereof.
3. The level lift and level drop-off arrangement of Claim 1, where the drop-
off point is a
collection box.

Description

CA 02308045 2001-02-23
hrlOr Art
'Che special arrangement of the vacuum transfer mechanism of this invention is
created to replace a
prior system of pushing rows of lightweight products from the upper surface at
the terminal end of
travel of a first conveyor on to and along the smooth surface of an
intervening slide plate to a
;;elected point on another conveyor continuing in the same direction. The
trailing edges of some
moulded pulp articles, such as apple trays, do not present a convenient
surface for the action of the
pusher bar, and the special arrangement of this invention provides a useful
and reliable method of
transfer.
Earlier known vacuum lift and transfi:r mechanisms as described in U.S. Patent
No. 4,560,060
(Lenhart, 1985) and U.S. Patent No. 5.,651,313 (Kowalewski et al, 1997) make
no provision for a
secure level lift and drop-off, and the related security against troublesome
misalignment of moulded
trays and the like in transport to the selected location.
Summary of the Invention
In a vacuum lift and transfer mechanism comprised of a belt conveyor having a
foraminous belt
made of rubber or other plastic materials and a vacuum chamber with a slotted
bottom panel
located directly above the lower run of said foraminous belt, said lower run
of said belt being
located directly above and close to t:he top surfaces of lightweight products
being transported
on a first conveyor and approachin~; the terminal end thereof, said products
being lifted and
attracted into contact with the underside of said lower run of said foraminous
belt and
maintained there by vacuum conditions transmitted through the slots of said
bottom panel of
said vacuum chamber, and thence through perforations in said foraminous belt
into the space
between said foraminous belt and the products travelling on said first
conveyor, said products
then being transported at the underside of said foraminous belt to a selected
drop-off point
beyond the terminal end of said first conveyor, with the lower run of said
foraminous belt
travelling in the same direction as said products on said first conveyor and
at a controlled
speed, then, according to this invention, the perforations in said foraminous
belt are arranged
in groups of at least two perforations, with at least one of said groups of
perforations
cooperating with each one of said products travelling on said first conveyor,
with at least one

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perforation of each said group cooperating with a rearward portion of one of
said products, and
at least one other perforation of said group cooperating with a forward
portion of said one
product, said foraminous belt being controlled to travel at precisely the same
speed as said
products travelling on said first conveyor, and adjusted to have each product
lifted
simultaneously at both rearward and forward positions of said perforations in
said group, the
slots in said bottom panel of said vacuum chamber being continuous in the
direction of travel
of said products with alternating beginning and drop-off ends cooperating
separately with the
rearward and forward positions of said perforations in said groups, whereby to
lift said
forward and said rearward portions of each said product simultaneously and
thus to maintain a
level position at the pick-up point, amd also to release said forward and
rearward portions
simultaneously, whereby to maintain a level position in releasing each said
product at a
selected drop-off point.
Fsrief Description of the Drawings
Figure 1 is a plan view of a vacuum lift and transfer mechanism located
directly above the
terminal end of an approaching tray conveyor and the receiving end of a
continuing conveyor,
in order to transfer products from one conveyor to the other.
Figure 2 is a diagrammatic cross-sectional plan view taken at line 1-1 of
Figure 3 to show the
arrangement of continuing slots in the bottom panel of the vacuum distribution
chamber of said
vacuum lift and transfer mechanism and their correspondence with perforations
in the transfer
conveyor belt and the products being transferred.
Figure 3 is a diagrammatic vertical cross-sectional view showing the location
of said vacuum
lift and transfer mechanism, together with its vacuum distribution chamber
located immediately
above the terminal end of the approaching tray conveyor and the receiving end
of the
continuing belt conveyor.
Figure 4 is a cross-sectional plan view, taken at line 3-3 of Figure 5 showing
the arrangement
of the continuous parallel lines of closely spaced perforations in the bottom
panel of the
vacuum distribution chamber superimposed over and cooperating with the larger
and more
widely spaced perforations in the transfer belt, and with the widely spaced
meat trays being
transferred from a belt conveyor to a collection box.
Figure 5 is a diagrammatic vertical cross-sectional view showing the location
of the vacuum lift
and transfer mechanism, together with its vacuum distribution chamber and
perforated transfer
Melt over the terminal end of the approaching belt conveyor and a collection
box.
Description of the Preferred Embodiments
'.Che vacuum lift and transfer conveyor' 300 shown in Figures 1, 2 and 3 is
comprised of a large
air blower 315 driven by motor 315X to create vacuum conditions in a vacuum
distribution
chamber 312, together with a foraminous conveyor belt 302 driven by a helper
motor 302X all
~,upported together for height adjustment on platform 304. The bottom panel of
said
distribution chamber projects below said platform, and is provided with a
series of long slots
;Z20 continuing along the length of said bottom panel, and parallel to the
sides thereof. The

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lower run of said belt 302 is maintained in close contact with the underside
of said bottom
panel, and vacuum conditions are transmitted through the slots 320, and thence
through the
cooperating perforations 321 and 322 in said belt 302, to the space between
the underside of
said belt 302 and the products 30 to b~e lifted and maintained in close
contact with the
underside of said belt 302 while they are being transferred along the travel
path of said belt
302 to the drop-off point on to the receiving conveyor 303. The travel speed
of said belt 302
is coordinated with the travel speed of the tray conveyor 301 by chain drive
311 so that one
group of a series of groups of 4 perforations in said belt 302 travels
directly over each product
30 transported on said tray conveyor 301, and at the same speed, with two of
said perforations
322 being located at a forward portion of each said product 30, and two of
said perforations
321 located at a rearward portion thereof, thereby to create a balanced
lifting, transporting and
drop-off force on each said product 30 throughout the period of their transfer
between said tray
conveyor 301 and said receiving conveyor 303, the cooperation between each of
said products
30 and the corresponding group of pf:rforations being regulated by the chain
drive 311 between
the shaft 310 of sprocket 315 of the tray conveyor 301 and the helper drive
shaft of the transfer
belt 302. The lift ends and the drop-off ends of slots 320 serving
perforations 322 are spaced
forward of the corresponding ends of the slots serving perforations 321 so
that the forward and
rearward perforations for each product act simultaneously at both the lift
points and the drop-
off points, whereby to maintain each said product 30 in a horizontal
orientation during the
entire transfer operation.
The vacuum lift and transfer mechanism 700 shown in Figures 4 and 5 is
comprised of a
vacuum distribution chamber 712 served by an air blower similar to the blower
315 shown in
Figure 1, together with a perforated conveyor belt 702 maintained in close
contact with the
underside of the bottom panel of said chamber 711, said bottom panel being
perforated by a
series of parallel rows of closely spaced round holes 720 as an alternative to
the continuous
slots in chambers 311 and 511, said rows of holes 720 being located along the
travel paths of
the perforations 721 and 722 in said belt 702, whereby to transmit vacuum
conditions to the
space between the underside of said belt 702 and the top surfaces of the
products 70 and
thereby to lift and maintain said products 70 in close contact with the
underside of said belt
conveyor 702 during the period of their transfer between conveyor 701 and the
drop-off at
collection box 703.

Representative Drawing